The present application pertains to bore drilling tool bits for forming bores in materials such as wood and the like.
Many aspects of the building construction industry involve installation of various means for providing services such as wiring, plumbing, and pipe fitting. These various disciplines, as well as others, involve attaching or routing such means through the structural components of a building.
For example, when a home is constructed, an initial step involves framing in the building or in other words assembling the wall studs, roof joists, floor joists, and other structural elements. Once the house is "framed in", and prior to installing wall covering materials, the service delivery disciplines such as electricians, plumbers, and pipe fitters, enter the structure in order to install their respective services.
By way of example, reference will be made to electrical installations in a home construction. An electrician will commonly route wiring between joists and wall studs, however, there are many instances where the wiring, or conduit, must pass through a joist or a wall stud. In such a situation, a bore must be formed through the structural element and the wiring threaded therethrough. While it is known that drill bits or bore forming tool bits may be used to form a bore in a structural element composed of wood or another material, this task becomes increasingly difficult with the thickness of the material as well as any obstructions which may pass through the bore path in the material. A typical method of providing stronger structural supports using wooden members is to attach two or more members by nails or other fasteners. Clearly, if an electrician is required to drill through an area where nails are embedded in the wood, the task of forming a bore through such a structural element can be difficult if not impossible.
A problem arises when forming a bore through such a structural element because of the type of bits which are currently available. While many bits will serve the purpose of forming a bore, even through nails extending through the bore path, such bits quickly become dull and various features of the bit may even fail during the boring operation. Spurs are often formed on the forwardmost surface along the circumferential edge of such surface for scribing the circumference of the bore. By scribing the circumference, the material within the circumference is more easily removed during the boring operation. However, due to the protruding shape of most spurs, when a nail is encountered in the bore path the spur may be either damaged or broken off of the head of the bore forming tool bit.
In order to overcome the problems encountered with spurs in such a bore forming operation, various bits have been developed which eliminate the spur. Elimination of the spur results in a bore hole that is rough and rather ragged with fibers extending from the surface of the bore when a bore is formed in a materials such as wood. The ragged internal surface of the bore is a result of wood being rather fibrous and stringy. If the fibers of the wood are not severed, such as is done by scribing the circumference of the bore with a spur, the fibers are torn and leave a ragged inside surface.
A ragged inside surface of a bore extending through several pieces of structural lumber presents a problem to electricians and other disciplines in that it hampers the routing of cables or pipes through such a bore. Further, the ragged inside surface may require a larger bore to be drilled through the structural lumber in order to compensate for the additional ragged fibers extending into the bore. It is desirable to form as small a bore as possible to maintain the highest structural integrity of the structural member. As such, it is not desirable to have a ragged inside surface of a bore.
Another consequence of bore drilling without scribing is that the surface around the perimeter of the exit hole is splintered. The splintered exit surface perimeter results from failing to sever the fibers of the exit surface causing the fibers to be ripped along the exit surface. Additionally, not only does a ragged and splintered bore become more difficult to work with and possibly weaken the structural integrity of the structural member, such workmanship is unsightly, aesthetically unpleasing, and looked down upon in the building trades industry.
Therefore, it would be desirable to provide a bore drilling tool bit which is capable of forming a bore through material such as wood and the like which forms a smooth inside surface in the bore during the boring operation. It is also desirable to provide a bore forming tool bit which is generally unaffected by nails or other obstructions extending through the material in the bore path. To our knowledge, such a bore forming tool bit is not available.